Light measuring device for a camera

Abstract

A light measuring apparatus for an exposure control for a camera including a photoelectric converter which photoelectrically converts a portion of a light beam impinging on a photoelectric conversion portion of a focus detection device, through a taking lens. The remainder of the light beam is transmitted into the optical path of the light beam so that light measuring for an exposure control is performed from the bundle of light proceeding toward the focus detection device.

What is claimed is: 
     
       1. A light measuring apparatus for a camera, comprising: (a) first light sensitive means for producing an electrical signal for focus detection in response to the illumination thereof; and   (b) second light sensitive means, positioned in the vicinity of an imaging plane of a taking lens, for converting a portion of a light beam passing through the taking lens into an electrical signal, and for permitting the remainder of the light beam to pass therethrough, wherein said second light sensitive means is positioned with respect to said first light sensitive means such that the remainder of the light beam illuminates said first light sensitive means, wherein said second light sensitive means comprises a plurality of light sensitive elements, wherein a portion of said plurality of elements blocks the light beam passing through the taking lens which would otherwise pass through said second light sensitive means and illuminate said first light sensitive means, and wherein the direction in which said first light sensitive means is oriented substantially coincides with the direction in which said plurality of light sensitive elements are oriented so as to uniformly distribute the remainder of the light beam on the first light sensitive means.   
     
     
       2. A light measuring apparatus according to claim 1, wherein said light sensitive elements are amorphous silicon light receiving elements. 
     
     
       3. A light measuring apparatus according to claim 1, wherein said light sensitive elements have photoelectric conversion parts which are separated from each other and are oriented parallel to each other. 
     
     
       4. A light measuring apparatus according to claim 3, wherein said comprise photoelectric conversion parts amorphous silicon light receiving elements. 
     
     
       5. A single lens reflex camera, comprising: (a) a taking lens;   (b) a focus detecting means comprising two electrical sensors for producing electrical signals in response to receiving an image of an object formed by light from said object passing through said taking lens, wherein said focus detecting means controls the focus condition of the taking lens in accordance with the correlation value associated with the object image and the output from said two electrical sensors; and   (c) light sensitive means positioned in the vicinity of an imaging plane of said taking lens, for converting a portion of a light beam passing through said taking lens into an electrical signal, for controlling an exposure value of said camera, and for permitting the remainder of the light beam to pass therethrough, wherein said light sensitive means is positioned relative to said focus detecting means such that the remainder of the light beam illuminates said two electrical sensors to control the focus state of said taking lens, wherein said light sensitive means comprises a plurality of light sensitive elements, wherein a portion of said plurality of elements block the light beam passing through said taking leans which would otherwise pass through said light sensitive means and illuminate said two electrical sensors, and wherein the direction in which said two electrical sensors are oriented substantially coincides with the direction in which said plurality of light sensitive elements are oriented so as to uniformly distribute the remainder of the light beam on the light sensitive means.   
     
     
       6. A single lens reflex camera according to claim 5, wherein each sensor comprises a CCD sensor.